As SaaS companies increasingly adopt usage-based pricing models, the need for robust billing infrastructure that supports complex metering, real-time tracking, and flexible pricing becomes crucial for developers. Knock, a company that uses such a model for its messaging infrastructure, emphasizes the importance of choosing the right billing platform to scale businesses efficiently. They highlight several platforms, including Orb, which offers a developer-friendly API and flexible pricing models, and Lago, an open-source platform providing full control over billing infrastructure. The text also discusses Metronome, Chargebee, and Zuora, each catering to different business needs from high-growth SaaS companies to large enterprises requiring extensive compliance certifications. Developers are encouraged to consider factors such as integration complexity, pricing flexibility, scalability, and developer experience when selecting a billing provider. Additionally, Knock underscores the importance of managing customer communication effectively around billing events, offering solutions that automate and optimize notification workflows to enhance customer experience without overwhelming them.